Discharge cleaning materials

Routine Process equipment cleaning Materials handling (discharge, conveying, bagging) Waste handling/deposition ... 

Relief valves are preferred for use on clean materials, because automatic closure prevents excessive discharge once excessive pressure is relieved. Rupture disks are less susceptible to plugging or other malfunctions but may allow complete emptying of the vessel, thus creating a safety or environmental hazard. Where fluctuating pressures or very corrosive conditions exist, or where polymerizable materials could prevent proper operation of a relief valve, some designers install two safety devices in series, ie, either two rupture disks or an upstream rupture disk followed by a relief valve. With either arrangement, it is imperative that the space between the two relief devices be monitored so that perforation or failure of the relief device closest to the vessel may be detected (86). 

The studies reviewed In this paper have produced data on the surface chemistry and vacuum behavior of a variety of technological materials, Including the effects of hydrogen discharge cleaning on structural metals such as stainless steel... 

Blistering has been couched traditionally in the context of materials performance in a fusion environment, and, as such, has been considered a problem in the longterm sense. There exists, however, some indication that blistering-like phenomena may occur when hydrogen discharge cleaning techniques are used to condition the plasma containment chamber walls of existing devices. (See Sect. 5.6.2.)... 

The most important parameters in glow-discharge cleaning are the type of applied voltage (AC or DC), the value of discharge voltage, the current density, type of gas and gas pressure, duration of treatment, type of material to be cleaned, shape and arrangement of electrodes. 

Effluent Guidelines and Standards. The Clean Water Act requires specific levels of control for dischargers. These are outlined in the Effluent Guidelines and Standards for various industrial categories. These standards limit the discharge of pollutants, usually in terms of a unit weight of pollutant per unit of either product or raw material, rather than a concentration in the discharge stream, in order to eliminate the use of dilution to meet limits. 

---